Slow Cooker Frosted Cookie Bars

INGREDIENTS

2 cups

butter (softened)

14 oz

sweetened condensed milk

2 tbsp

baking powder

1 tsp

salt

2 tsp

vanilla extract

4 cups

all purpose flour

1 cup

white chocolate chips

1 3/4 oz

rainbow sprinkles ((plus more for topping, if desired))

1 cup

butter at room temperature

4 cups

powdered sugar

1 tbsp

vanilla extract

4 tbsp

heavy cream

drops (or more food coloring, if desired)